This question is about as close as you can come to the proverbial can of worms. Since I tend to err on the side of responsibility, I’m going to suggest you not attempt to make a citizen’s arrest. I suggest this for lots of reasons.
First up, let’s define a citizen’s arrest. Quite simply, a citizen’s arrest is an arrest or detention made by a person who is not acting as a sworn law enforcement officer. As simple as this sounds, this is where all the trouble starts. A sworn law enforcement officer is someone who has been hired or appointed by a government body, has taken an oath of office and is granted powers of arrest by that government body. Such officers have certain rules they must follow and also have certain protections granted to them as they perform their duties. For instance, depending on your jurisdiction, private citizens can be held to stricter liability than law enforcement officers when it comes to arresting or detaining someone suspected of committing a crime. Police officers can also detain anyone for a reasonable amount of time based on a reasonable suspicion that a crime has been committed. Private citizens may not. In most cases, the crime must be committed in the presence of the person making the citizen’s arrest.
In many cases, you may detain a person who you believe has committed a crime. But remember, if you are mistaken, you open yourself up to both civil and criminal liability, including false arrest, unlawful detention and even kidnapping.
Things get really cloudy with the use of force. First up, any use of force must be objectively reasonable. You can use only the force that will stop the action, and it must be deemed reasonable under the circumstances. The definition of “reasonable” will change from one jurisdiction to another and even from one person to another. But know this: You will not be the one determining if your actions were reasonable. Someone else will decide, and that decision will be influenced by the nature of the offense and the amount of force used to overcome any resistance.
For instance, if you step in and attempt to stop a car theft or a burglary, and the thief decides to fight you, and you end up shooting him, what do you think will happen? Ask George Zimmerman.
I fall firmly in the camp of the good witness. If you happen upon a crime in progress, give verbal commands and be prepared to defend yourself if the criminal turns on you. If the criminal is unarmed and not committing an act of violence, keep your gun holstered, but be ready. If the crime is violent, you may draw your gun and issue commands at gunpoint if you believe the actions pose an imminent threat of death or great bodily harm. If the criminal runs away, let him go.
Call 911 and be a good witness. Let the police catch the crook another day. Stay safe and be responsible in your actions.